Diamond Viper Radeon HD 4850 Review

As a standalone 3D graphics card, and depending on the game, AMD’s new $199 ATI Radeon HD 4850 is very competitive with Nvidia’s $229 GeForce 9800 GTX+. What’s potentially more exciting is that the 4850 also seems to scale better in dual-card Crossfire mode than anything Nvidia has for the same price. It’s also only a single-slot card, which gives you more flexibility in the kind of system you can use it with. Physical convenience aside, if the price on the 4850 falls to the $150 range (which is very possible), it will be time to get legitimately excited about the sheer value found in this new card. Right now, it’s only a pretty good standalone part. If you’re looking for a relatively inexpensive dual-card upgrade, however, the Radeon HD 4850 is worth getting excited about right away.

The Radeon HD 4850 chip is AMD’s second 55 nanometer part, and on paper, it seems to compare well with the GeForce 9800 GTX+.

The specifications to notice here is the stream processor count and the stream processor clock speed. The stream processors paths are essentially where the 3D graphics magic happens. Therein the card processes all of the geometry, the various shaders, and other components of the scene. It’s also where the card-based computing takes place, about which Nvidia has been making a lot of noise over the past few months. AMD has its own implementation of GPU processing, which we’ll get to shortly.

We wish we could track down the shader clock speed for the Radeon HD 4850. The driver software doesn’t report it, and we couldn’t get AMD to provide us with a number. Its 800 streams look impressive compared with the GeForce 9800GTX+ 120 count, but that might not matter as much if the Radeon HD 4850’s speed is significantly slower than the 9800’s 1,836MHz rating. The results in our performance charts make us think that whatever Radeon HD 4850’s stream speed is, that’s probably the case.

As usual, Sarju Shah at GameSpot was kind enough to share his test results with us. From a single card perspective, we find the Radeon HD 4850’s Crysis scores average, its Team Fortress 2 scores outstanding, and its Call of Duty 4 scores unimpressive. On the whole, we translate those scattershot results to mean that for most games, the Radeon HD 4850 will provide acceptable performance, even on a 24-inch LCD at their native resolution. Smaller displays and resolutions will run very smoothly, although in every case you’ll likely need to dial down the image quality settings. You may also feel a noticeable performance crunch around the end of August or the beginning of September when we expect a fresh crop of challenging PC titles.

In dual-card mode, the Radeon HD 4850 makes up quite a bit of ground on Call of Duty 4, it simply kills Team Fortress 2, and Crysis becomes a lot better. In fairness, while the GeForce 9800 GTX+ doesn’t seem to scale at all in SLI mode on Crysis, it could be because of early drivers. We’re willing to give it leeway as that card isn’t due at retail until July. But even if Nvidia’s competing card did improve with a new driver, suddenly you’re looking at $460 for two cards, and four expansion slots occupied in your PC, compared with only two slots about $400 for a pair of Radeon HD 4850’s. That combination of performance, flexibility, and value, makes the Radeon HD 4850 in Crossfire mode look very promising.

The GPU as a computer
As we mentioned earlier (and explained extensively in our GeForce GTX 280 review), Nvidia has been making a lot of noise lately about the potential for graphics cards to do more than accelerate 3D games. If you think of all of those stream processors similar to the way in which you look at a dual-core or quad-core CPU, suddenly the 3D card becomes a lot more useful. Only certain kinds of applications, mostly involving multimedia processing, make sense to move to the 3D card, but once that happens, all of those streams present some great opportunities. All of Nvidia’s GeForce cards from the 8000 series on up have this capability, and AMD also boasts that all of its cards from the Radeon 1000 series and forward can do it as well.

But as usual, you need the software to tell the hardware what to do. Nvidia’s will rely on software developers to support Nvidia’s Cuda programming language. AMD is counting on industry standards, including Apple’s OpenCL to funnel software to its GPUs. Right now, one of the only things you can play with is separate versions of Folding@Home, one geared for AMD’s cards, and another for Nvidia’s.

While we of course find the Folding@Home research valuable, there are no other consumer-level applications that put GPU computing to work at the moment. The most promising one on the horizon is Adobe’s next version of its Creative Suite, which is also supposed to work with both AMD and Nvidia GPUs.

Aside from general computing, the GPU is also ripe for assisting with game physics. Nvidia has pointed out a few games with dedicated levels that use the PhysX standard of its recent acquisition Ageia. For its part, AMD has signed a deal with Ageia’s competitor, Havok, whose Havok Engine has long been the industry standard for applying physics to games. As we said earlier, this battle still needs time to play out, and there’s a very real chicken-and-egg problem as far as game developer implementation, hardware adoption, and overall gamer interest. As much as we like the idea of enhanced physical properties in games, we’ll need to see more than specialized, one-off levels before we can get that excited about GPU physics processing.

Installation and additional features
To add a single Radeon HD 4850 into your PC, you’ll need a free PCI Express graphics card slot, and 450-watt power supply, and a single six-pin power supply input. For two of them, AMD recommends only a 650 watt power supply. We found that the cards get very hot, even only a few seconds after the initial boot, so you’ll want to make sure that your case has adequate cooling, especially if you intend to use more than one card.

The Radeon HD 4850 also boasts the typical features of most modern graphics cards, as well as a few extras. It can play protected HD video content, although the Diamond Viper card we received has no HDMI-output. Instead you get two DVI-outs and an adapter input for component video out, as well as a DVI-to-HDMI adapter, among others.

Like most new 3D cards, the Radeon HD 4850 will support the PCI Express 2.0 standard, and it’s also, of course, DirectX 10 compatible. AMD also trumpets this card’s DirectX 10.1 capability; however, similar to GPU computing and GPU physics, the games aren’t quite there yet, so we don’t think that feature is enough to justify a purchase.

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